| Date | November 2020 | Marks available | 1 | Reference code | 20N.2.SL.TZ0.2 |
| Level | Standard level | Paper | Paper 2 | Time zone | TZ0 / no time zone |
| Command term | State | Question number | 2 | Adapted from | N/A |
Question
The photomicrograph below shows the protozoan Paramecium caudatum.
[Source: Deuterostome, CC BY-SA 3.0
https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons.]
State the genus of this organism.
State the domain in which it is classified.
Outline the method of nutrition carried out by P. caudatum.
Outline one aspect of how P. caudatum carries out homeostasis.
Apart from the ribosomes, explain the evidence for the endosymbiotic theory of the origin of eukaryotic cells.
Markscheme
Paramecium
eukaryotes
heterotroph/consumer as it feeds on bacteria/algae/yeast/smaller single celled organisms
OR
heterotroph/consumer as it does not have chloroplasts
Heterotrophic must be qualified.
a. lives in fresh water so water enters cell (by osmosis);
b. contractile vacuoles collect and expel water;
c. homeostasis is keeping internal conditions within limit/constant / involves osmoregulation/regulating water content/potential;
a. mitochondria/chloroplasts show features in common with prokaryotes/similar size;
b. multiply by binary fission/in same manner;
c. have naked loop of DNA/circular DNA/own DNA;
d. surrounded by a double membrane;
Examiners report
In a about half of the candidates named the genus correctly (Paramaecium), but significantly fewer could state the correct domain (eukaryota). The most common wrong answers were prokaryote and eubacteria. Only the better candidates were able to outline the method of nutrition (heterotrophy) in b and describe how homeostasis is carried out, in spite of being specifically stated in the syllabus. The endosymbiotic theory was quite well known.
Syllabus sections
- 17N.1.SL.TZ0.22: Which of the organisms A–D, identified by the key, represents a reptile?
- 18M.2.SL.TZ1.4a.ii: State the plant phylum which is characterised by the absence of vascular tissue.
- 18M.1.SL.TZ2.22: Which invertebrate phylum is characterized by a segmented body and bilateral symmetry? A....
- 18N.2.SL.TZ0.3a: Identify the dominant plant phylum in the boreal forest.
- 21M.1.SL.TZ1.23: A locust is an arthropod. For invertebrate groups, which recognition feature is found only in...
- 16N.1.SL.TZ0.23: The scientific name of the Wakatobi flowerpecker is Dicaeum kuehni. Which species is most...
- 16N.1.SL.TZ0.22: In which domain are bryophyta found? A. PlantaeB. ArchaeaC. EubacteriaD. Eukaryote
- 18M.2.SL.TZ1.4a.i: State one reason that viruses are not classified as living organisms.
- 19M.1.SL.TZ2.22: Which phyla have bilateral symmetry? A. annelida, arthropoda, platyhelmintha B. porifera,...
- 17M.1.SL.TZ2.22: The diagram represents a cladogram of the family Procyonidae. What would justify...
- 19N.1.SL.TZ0.22: An organism has the following characteristics: single opening for ingestion and...
- 22M.1.SL.TZ2.22: The diagram shows features of three plant phyla. Which phyla are represented by R, S and T?
- 17M.1.HL.TZ1.18: An animal shows radial symmetry, has only one opening leading to a digestive cavity and is...
- 17M.1.SL.TZ1.23: A plant has cambium in its vascular tissue and pollen is produced in male cones. The plant...
-
21M.1.SL.TZ2.22:
The images show a structure found on members of a phylum of green plants.
[Source: left: Pratheep P S, www.pratheep.com (CC BY-SA 3.0) https://creativecommons.org right: Curtis Clark (CC BY-SA 3.0) https://creativecommons.org/licenses/by-sa/3.0/.]
What is the name of the phylum to which the organisms belong?
A. Coniferophyta
B. Angiospermophyta
C. Filicinophyta
D. Bryophyta
- 17M.1.SL.TZ1.22: Below is a phylogenetic tree of the three domains. There are important differences between...
- 19M.2.HL.TZ2.4a: The images show parts of plants belonging to two different phyla. State the phylum of...
- 19M.2.SL.TZ1.5c: Identify two species from the list that are classified in different genera. 1. 2.
-
19M.1.SL.TZ1.22:
The image shows an organism belonging to the Kingdom Animalia.
[Source: Titan beetle male. Locality: “RK4,5 route Cacao”, French Guiana
© 2011, Didier Descouens https://creativecommons.org/licenses/by-sa/4.0/]What feature does this organism have in common with all members of the phylum chordata?
A. Legs and wings
B. Mouth but no anus
C. Bilateral symmetry
D. Chitinous exoskeleton
- 19M.1.SL.TZ2.21: If seeds of an unknown species of plant are discovered, what assumption can be made about the...
- 17M.1.SL.TZ2.23: Which is a characteristic of both bryophyta and filicinophyta? A. Vascular tissue B....
- 17M.2.HL.TZ2.4b: State the name of the domain to which birds, such as the Elf owl, belong.
- 17M.2.SL.TZ2.4b: State two characteristics that identify lice as members of the arthropoda. 1. 2.
- 16N.1.HL.TZ0.19: The scientific name of the great egret has recently been changed from Casmerodius albus to...
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
-
21N.2.SL.TZ0.6c:
Outline the binomial system of classification.
- 17N.2.SL.TZ0.04a.i: State the phylum of this plant.
- 19M.1.HL.TZ2.28: Which is the hierarchy of taxa in order of increasing numbers of species? A. genus, family,...
-
18M.2.SL.TZ1.4b:
C. nemoralis (pictured below) is a mollusc. Identify two external features that distinguish this snail from an arthropod.
-
21N.1.SL.TZ0.22:
The image shows the northern sea nettle (Chrysaora melanaster).
[Source: Aflo, 2015. Northern sea nettle (Chrysaora Melanaster) floating, with Mackerel fry (Carangidae) Izu, Japan. [image
online] Available at: https://www.naturepl.com/search/preview/northern-sea-nettle-chrysaora-melanaster-floating-withmackerel-
fry-/0_01489405.html [Accessed 23 March 2020].]To which phylum does C. melanaster belong?
A. Porifera
B. Cnidaria
C. Platyhelmintha
D. Annelida
-
21N.1.HL.TZ1.18:
To which phylum does the earthworm Lumbricus rubellus belong?
[Source: Casselmann, H., 2011. Lumbricus rubellus HC1. [image online] Available at: https://commons.wikimedia.org/
wiki/File:Lumbricus_rubellus_HC1.jpg (CC BY-SA 3.0) https://creativecommons.org/licenses/by-sa/3.0/deed.en [Accessed 23 March 2020].]A. Annelida
B. Cnidaria
C. Platyhelmintha
D. Arthropoda
- 19N.2.HL.TZ0.1a: State the domain into which ticks are classified.
- 19N.2.HL.TZ0.1c: Identify the month when small birds had the greatest chance of being infected by B....
-
17N.2.SL.TZ0.04a.ii:
State two characteristics of plants from the phylum you stated in (a)(i).
-
16N.2.SL.TZ0.5a:
Living organisms have been placed in three domains: archaea, eubacteria and eukaryote. Distinguish archaea from eubacteria.
- 18N.1.SL.TZ0.22: The chart shows features of three organisms X, Y and Z. To which domain does each organism...
- 18N.1.SL.TZ0.20: The images show a guinea pig, a mouse, a horse and a whale. Which features support the...
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
-
19N.1.SL.TZ0.23:
Which organism is a member of the filicinophyta? (Note that these are not to scale)
[Source: A: Sanjay ach/https://creativecommons.org/licenses/by-sa/3.0/deed.en
B: Vaelta/https://creativecommons.org/licenses/by-sa/3.0/deed.en
C: Andrey Zharkikh/https://creativecommons.org/licenses/by/2.0/deed.en
D: courtesy of Caroline Needham] -
22M.1.SL.TZ1.22:
The plant in the diagram has vascular tissue and reproduces by spores.
[Source: Auer, A., 2007. Nature print, Alois Auer. [image online] Available at: https://commons.wikimedia.org/wiki/File:Nature_print,_Alois_Auer.jpg [Accessed 10 October 2019].]
To which phylum does the plant belong?
A. Bryophyta
B. Filicinophyta
C. Coniferophyta
D. Angiospermophyta
-
22M.2.SL.TZ1.1i:
State one feature of the sloth that would indicate it is a mammal.
- 21M.1.SL.TZ1.24: A dichotomous key can be used to distinguish four types of plant. Which of the plants could...
- 18M.1.SL.TZ1.22: Which phylum shows radial symmetry? A. Annelida B. Cnidaria C. Platyhelmintha D. Porifera
- 18N.2.HL.TZ0.4a: Identify the dominant plant phylum in the boreal forest.
- 19M.2.SL.TZ1.5b: Identify the two species most closely related. 1. 2.
- 19M.2.SL.TZ2.4a: The images show parts of plants belonging to two different phyla. State the phylum of...
- 21M.2.HL.TZ2.3c: State the genus of the broad bean.
- 19N.2.HL.TZ0.1e: Evaluate the effect of the change in distribution of the different life stages of ticks on...
- 19N.2.HL.TZ0.1d: Using the life cycle diagram and the graph for the year 2000, analyse the distribution of...
- 19N.2.HL.TZ0.1b: Using information from the text, identify one possible simple treatment for Lyme disease.
-
18M.2.HL.TZ1.2a:
State two features that are found only in mammals.
- 20N.1.SL.TZ0.22: An animal has the following characteristics: bilateral symmetry, mouth but no anus, ribbon...
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
-
20N.2.SL.TZ0.2a.i:
State the genus of this organism.
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
-
17M.2.SL.TZ1.4c:
Taxonomists aim to place species into genera, families and higher taxa according to their evolutionary origins. This is known as natural classification.
Explain the usefulness of natural classification in biodiversity research.
- 19M.1.SL.TZ2.23: Which is the hierarchy of taxa in order of decreasing numbers of species? A. domain, phylum,...
- 19M.2.SL.TZ1.5a: State one feature that characterizes these species as mammals.
- 19M.2.HL.TZ2.4b: Some plant families, such as the figwort family, have been reclassified on the basis of...
